/**
* Copyright (C) 2008 Happy Fish / YuQing
*
* FastDFS Java Client may be copied only under the terms of the GNU Lesser
* General Public License (LGPL).
* Please visit the FastDFS Home Page http://www.csource.org/ for more detail.
*/

package org.csource.fastdfs;

import java.io.IOException;
import java.io.OutputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.File;
import java.util.Arrays;
import java.net.Socket;
import org.csource.common.MyException;
import org.csource.common.NameValuePair;
import org.csource.common.Base64;

/**
* Storage client for 2 fields file id: group name and filename
* @author Happy Fish / YuQing
* @version Version 1.24
*/
public class StorageClient
{
	/**
	* Upload file by file buff
	* @author Happy Fish / YuQing
	* @version Version 1.12
	*/
	public static class UploadBuff implements UploadCallback
	{
		private byte[] fileBuff;
		private int offset;
		private int length;
		
		/** 
		* constructor
		* @param fileBuff the file buff for uploading
		*/
		public UploadBuff(byte[] fileBuff, int offset, int length)
		{
			super();
			this.fileBuff = fileBuff;
			this.offset = offset;
			this.length = length;
		}
	
		/**
		* send file content callback function, be called only once when the file uploaded
		* @param out output stream for writing file content
		* @return 0 success, return none zero(errno) if fail
		*/
		public int send(OutputStream out) throws IOException
		{
			out.write(this.fileBuff, this.offset, this.length);
			
			return 0;
		}
	}
	
	public final static Base64 base64 = new Base64('-', '_', '.', 0);
	protected TrackerServer trackerServer;
	protected StorageServer storageServer;
	protected byte errno;
	
/**
* constructor using global settings in class ClientGlobal
*/
	public StorageClient()
	{
		this.trackerServer = null;
		this.storageServer = null;
	}
	
/**
* constructor with tracker server and storage server
* @param trackerServer the tracker server, can be null
* @param storageServer the storage server, can be null
*/
	public StorageClient(TrackerServer trackerServer, StorageServer storageServer)
	{
		this.trackerServer = trackerServer;
		this.storageServer = storageServer;
	}

/**
* get the error code of last call
* @return the error code of last call
*/
	public byte getErrorCode()
	{
		return this.errno;
	}

	/**
	* upload file to storage server (by file name)
	* @param local_filename local filename to upload
	* @param file_ext_name file ext name, do not include dot(.), null to extract ext name from the local filename
	* @param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file </li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String local_filename, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final String group_name = null;
		return this.upload_file(group_name, local_filename, file_ext_name, meta_list);
	}
	
	/**
	* upload file to storage server (by file name)
	* @param group_name the group name to upload file to, can be empty
	* @param local_filename local filename to upload
	* @param file_ext_name file ext name, do not include dot(.), null to extract ext name from the local filename
	* @param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file </li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	protected String[] upload_file(String group_name, String local_filename, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final byte cmd = ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_FILE;
		return this.upload_file(cmd, group_name, local_filename, file_ext_name, meta_list);
	}

	/**
	* upload file to storage server (by file name)
	* @param cmd the command
	* @param group_name the group name to upload file to, can be empty
	* @param local_filename local filename to upload
	* @param file_ext_name file ext name, do not include dot(.), null to extract ext name from the local filename
	* @param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file </li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	protected String[] upload_file(byte cmd, String group_name, String local_filename, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		File f = new File(local_filename);
		FileInputStream fis = new FileInputStream(f);
		
		if (file_ext_name == null)
		{
			int nPos = local_filename.lastIndexOf('.');
			if (nPos > 0 && local_filename.length() - nPos <= ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN + 1)
			{
				file_ext_name = local_filename.substring(nPos+1);
			}
		}
		
		try
		{
		  return this.do_upload_file(cmd, group_name, null, null, file_ext_name, 
		           f.length(), new UploadStream(fis, f.length()), meta_list);
		}
		finally
		{
			fis.close();
		}
	}

	/**
	* upload file to storage server (by file buff)
	* @param file_buff file content/buff
	* @param offset start offset of the buff
	* @param length the length of buff to upload
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(byte[] file_buff,	int offset, int length, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final String group_name = null;
		return this.upload_file(group_name, file_buff, offset, length, file_ext_name, meta_list);
	}
	
	/**
	* upload file to storage server (by file buff)
	* @param group_name the group name to upload file to, can be empty
	* @param file_buff file content/buff
	* @param offset start offset of the buff
	* @param length the length of buff to upload
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, byte[] file_buff, int offset, int length,	
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_FILE, group_name, null, null, file_ext_name, 
		           length, new UploadBuff(file_buff, offset, length), meta_list);
	}
	
	/**
	* upload file to storage server (by file buff)
	* @param file_buff file content/buff
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(byte[] file_buff, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final String group_name = null;
		return this.upload_file(group_name, file_buff, 0, file_buff.length, file_ext_name, meta_list);
	}
	
	/**
	* upload file to storage server (by file buff)
	* @param group_name the group name to upload file to, can be empty
	* @param file_buff file content/buff
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to store the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, byte[] file_buff,	
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_FILE, group_name, null, null, file_ext_name, 
		           file_buff.length, new UploadBuff(file_buff, 0, file_buff.length), meta_list);
	}
	
	
	/**
	* upload file to storage server (by callback)
	* @param group_name the group name to upload file to, can be empty
	* @param file_size the file size
	* @param callback the write data callback object
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, long file_size, UploadCallback callback, 
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		final String master_filename = null;
		final String prefix_name = null;
		
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_FILE, group_name, master_filename, prefix_name, 
           file_ext_name, file_size, callback, meta_list);
	}
	
	/**
	* upload file to storage server (by file name, slave file mode)
	* @param group_name the group name of master file
	* @param master_filename the master file name to generate the slave file
	* @param prefix_name the prefix name to generate the slave file
	* @param local_filename local filename to upload
	* @param file_ext_name file ext name, do not include dot(.), null to extract ext name from the local filename
	* @param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file </li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, String master_filename, String prefix_name, 
         String local_filename, String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		if ((group_name == null || group_name.length() == 0) || 
		    (master_filename == null || master_filename.length() == 0) ||
		    (prefix_name == null))
		{
			throw new MyException("invalid arguement");
		}
		
		File f = new File(local_filename);
		FileInputStream fis = new FileInputStream(f);
		
		if (file_ext_name == null)
		{
			int nPos = local_filename.lastIndexOf('.');
			if (nPos > 0 && local_filename.length() - nPos <= ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN + 1)
			{
				file_ext_name = local_filename.substring(nPos+1);
			}
		}
		
		try
		{
		  return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name, 
		                           file_ext_name, f.length(), new UploadStream(fis, f.length()), meta_list);
    }
    finally
    {
    	fis.close();
    }
	}
	
	/**
	* upload file to storage server (by file buff, slave file mode)
	* @param group_name the group name of master file
	* @param master_filename the master file name to generate the slave file
	* @param prefix_name the prefix name to generate the slave file
	* @param file_buff file content/buff
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, String master_filename, String prefix_name, 
	       byte[] file_buff, String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		if ((group_name == null || group_name.length() == 0) || 
		    (master_filename == null || master_filename.length() == 0) ||
		    (prefix_name == null))
		{
			throw new MyException("invalid arguement");
		}

		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name, 
		                           file_ext_name, file_buff.length, new UploadBuff(file_buff, 0, file_buff.length), meta_list);
	}
	
	/**
	* upload file to storage server (by file buff, slave file mode)
	* @param group_name the group name of master file
	* @param master_filename the master file name to generate the slave file
	* @param prefix_name the prefix name to generate the slave file
	* @param file_buff file content/buff
	* @param offset start offset of the buff
	* @param length the length of buff to upload
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, String master_filename, String prefix_name, 
	       byte[] file_buff, int offset, int length, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		if ((group_name == null || group_name.length() == 0) || 
		    (master_filename == null || master_filename.length() == 0) ||
		    (prefix_name == null))
		{
			throw new MyException("invalid arguement");
		}

		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name, 
		            file_ext_name, length, new UploadBuff(file_buff, offset, length), meta_list);
	}

	/**
	* upload file to storage server (by callback, slave file mode)
	* @param group_name the group name to upload file to, can be empty
	* @param master_filename the master file name to generate the slave file
	* @param prefix_name the prefix name to generate the slave file
	* @param file_size the file size
	* @param callback the write data callback object
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_file(String group_name, String master_filename, 
	       String prefix_name, long file_size, UploadCallback callback, 
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_SLAVE_FILE, group_name, master_filename, prefix_name, 
           file_ext_name, file_size, callback, meta_list);
	}
	
	/**
	* upload appender file to storage server (by file name)
	* @param local_filename local filename to upload
	* @param file_ext_name file ext name, do not include dot(.), null to extract ext name from the local filename
	* @param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file </li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_appender_file(String local_filename, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final String group_name = null;
		return this.upload_appender_file(group_name, local_filename, file_ext_name, meta_list);
	}
	
	/**
	* upload appender file to storage server (by file name)
	* @param group_name the group name to upload file to, can be empty
	* @param local_filename local filename to upload
	* @param file_ext_name file ext name, do not include dot(.), null to extract ext name from the local filename
	* @param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file </li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	protected String[] upload_appender_file(String group_name, String local_filename, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final byte cmd = ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE;
		return this.upload_file(cmd, group_name, local_filename, file_ext_name, meta_list);
	}

	/**
	* upload appender file to storage server (by file buff)
	* @param file_buff file content/buff
	* @param offset start offset of the buff
	* @param length the length of buff to upload
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_appender_file(byte[] file_buff,	int offset, int length, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final String group_name = null;
		return this.upload_appender_file(group_name, file_buff, offset, length, file_ext_name, meta_list);
	}
	
	/**
	* upload appender file to storage server (by file buff)
	* @param group_name the group name to upload file to, can be empty
	* @param file_buff file content/buff
	* @param offset start offset of the buff
	* @param length the length of buff to upload
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_appender_file(String group_name, byte[] file_buff, int offset, int length,	
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, null, null, file_ext_name, 
		           length, new UploadBuff(file_buff, offset, length), meta_list);
	}
	
	/**
	* upload appender file to storage server (by file buff)
	* @param file_buff file content/buff
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_appender_file(byte[] file_buff, String file_ext_name, 
	       NameValuePair[] meta_list) throws IOException, MyException
	{
		final String group_name = null;
		return this.upload_appender_file(group_name, file_buff, 0, file_buff.length, file_ext_name, meta_list);
	}
	
	/**
	* upload appender file to storage server (by file buff)
	* @param group_name the group name to upload file to, can be empty
	* @param file_buff file content/buff
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_appender_file(String group_name, byte[] file_buff,	
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, null, null, file_ext_name, 
		           file_buff.length, new UploadBuff(file_buff, 0, file_buff.length), meta_list);
	}
	
	/**
	* upload appender file to storage server (by callback)
	* @param group_name the group name to upload file to, can be empty
	* @param file_size the file size
	* @param callback the write data callback object
	* @param file_ext_name file ext name, do not include dot(.)
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*           <ul><li>results[0]: the group name to berth the file</li></ul>
	*           <ul><li>results[1]: the new created filename</li></ul>
	*         return null if fail
	*/
	public String[] upload_appender_file(String group_name, long file_size, UploadCallback callback, 
	       String file_ext_name, NameValuePair[] meta_list) throws IOException, MyException
	{
		final String master_filename = null;
		final String prefix_name = null;
		
		return this.do_upload_file(ProtoCommon.STORAGE_PROTO_CMD_UPLOAD_APPENDER_FILE, group_name, master_filename, prefix_name, 
           file_ext_name, file_size, callback, meta_list);
	}

	/**
	* append file to storage server (by file name)
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param local_filename local filename to append
	* @return 0 for success, != 0 for error (error no)
	*/
	public int append_file(String group_name, String appender_filename, String local_filename) throws IOException, MyException
	{
		File f = new File(local_filename);
		FileInputStream fis = new FileInputStream(f);
		
		try
		{
			return this.do_append_file(group_name, appender_filename, f.length(), new UploadStream(fis, f.length()));
		}
		finally
		{
			fis.close();
		}
	}
	
	/**
	* append file to storage server (by file buff)
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_buff file content/buff
	* @return 0 for success, != 0 for error (error no)
	*/
	public int append_file(String group_name, String appender_filename, byte[] file_buff) throws IOException, MyException
	{
		return this.do_append_file(group_name, appender_filename, file_buff.length, new UploadBuff(file_buff, 0, file_buff.length));
	}
	
	/**
	* append file to storage server (by file buff)
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_buff file content/buff
	* @param offset start offset of the buff
	* @param length the length of buff to append
	* @return 0 for success, != 0 for error (error no)
	*/
	public int append_file(String group_name, String appender_filename, 
	       byte[] file_buff, int offset, int length) throws IOException, MyException
	{
		return this.do_append_file(group_name, appender_filename, length, new UploadBuff(file_buff, offset, length));
	}

	/**
	* append file to storage server (by callback)
	* @param group_name the group name to append file to
	* @param appender_filename the appender filename
	* @param file_size the file size
	* @param callback the write data callback object
	* @return 0 for success, != 0 for error (error no)
	*/
	public int append_file(String group_name, String appender_filename, 
	       long file_size, UploadCallback callback) throws IOException, MyException
	{
		return this.do_append_file(group_name, appender_filename, file_size, callback);
	}

	/**
	* modify appender file to storage server (by file name)
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_offset the offset of appender file
	* @param local_filename local filename to append
	* @return 0 for success, != 0 for error (error no)
	*/
	public int modify_file(String group_name, String appender_filename, 
			long file_offset, String local_filename) throws IOException, MyException
	{
		File f = new File(local_filename);
		FileInputStream fis = new FileInputStream(f);
		
		try
		{
		  return this.do_modify_file(group_name, appender_filename, file_offset, 
			  	f.length(), new UploadStream(fis, f.length()));
		}
		finally
		{
			fis.close();
		}
	}
	
	/**
	* modify appender file to storage server (by file buff)
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_offset the offset of appender file
	* @param file_buff file content/buff
	* @return 0 for success, != 0 for error (error no)
	*/
	public int modify_file(String group_name, String appender_filename, 
			long file_offset, byte[] file_buff) throws IOException, MyException
	{
		return this.do_modify_file(group_name, appender_filename, file_offset, 
				file_buff.length, new UploadBuff(file_buff, 0, file_buff.length));
	}
	
	/**
	* modify appender file to storage server (by file buff)
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_offset the offset of appender file
	* @param file_buff file content/buff
	* @param buffer_offset start offset of the buff
	* @param buffer_length the length of buff to modify
	* @return 0 for success, != 0 for error (error no)
	*/
	public int modify_file(String group_name, String appender_filename, 
	       long file_offset, byte[] file_buff, int buffer_offset, int buffer_length) throws IOException, MyException
	{
		return this.do_modify_file(group_name, appender_filename, file_offset, 
				buffer_length, new UploadBuff(file_buff, buffer_offset, buffer_length));
	}

	/**
	* modify appender file to storage server (by callback)
	* @param group_name the group name to modify file to
	* @param appender_filename the appender filename
	* @param file_offset the offset of appender file
	* @param modify_size the modify size
	* @param callback the write data callback object
	* @return 0 for success, != 0 for error (error no)
	*/
	public int modify_file(String group_name, String appender_filename, 
	       long file_offset, long modify_size, UploadCallback callback) throws IOException, MyException
	{
		return this.do_modify_file(group_name, appender_filename, file_offset, 
				modify_size, callback);
	}
	
	/**
	* upload file to storage server
	* @param cmd the command code
	* @param group_name the group name to upload file to, can be empty
	* @param master_filename the master file name to generate the slave file
	* @param prefix_name the prefix name to generate the slave file
  * @param file_ext_name file ext name, do not include dot(.)
	* @param file_size the file size
	* @param callback the write data callback object
	*	@param meta_list meta info array
	* @return  2 elements string array if success:<br>
	*          <ul><li> results[0]: the group name to berth the file</li></ul>
	*          <ul><li> results[1]: the new created filename</li></ul> 
	*         return null if fail
	*/
	protected String[] do_upload_file(byte cmd, String group_name, String master_filename, 
	         String prefix_name, String file_ext_name, long file_size, UploadCallback callback, 
           NameValuePair[] meta_list) throws IOException, MyException
	{
		byte[] header;
		byte[] ext_name_bs;
		String new_group_name;
		String remote_filename;
		boolean bNewConnection;
		Socket storageSocket;
		byte[] sizeBytes;
		byte[] hexLenBytes;
		byte[] masterFilenameBytes;
		boolean bUploadSlave;
		int offset;
		long body_len;

		bUploadSlave = ((group_name != null && group_name.length() > 0) && 
		                (master_filename != null && master_filename.length() > 0) &&
		                (prefix_name != null));
		if (bUploadSlave)
		{
			bNewConnection = this.newUpdatableStorageConnection(group_name, master_filename);
		}
		else
		{
			bNewConnection = this.newWritableStorageConnection(group_name);
		}
		
		try
		{
			storageSocket = this.storageServer.getSocket();
			
			ext_name_bs = new byte[ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN];
			Arrays.fill(ext_name_bs, (byte)0);
			if (file_ext_name != null && file_ext_name.length() > 0)
			{
				byte[] bs = file_ext_name.getBytes(ClientGlobal.g_charset);
				int ext_name_len = bs.length;
				if (ext_name_len > ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN)
				{
					ext_name_len = ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN;
				}
				System.arraycopy(bs, 0, ext_name_bs, 0, ext_name_len);
			}
			
			if (bUploadSlave)
			{
				masterFilenameBytes = master_filename.getBytes(ClientGlobal.g_charset);
				
				sizeBytes = new byte[2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE];
				body_len = sizeBytes.length + ProtoCommon.FDFS_FILE_PREFIX_MAX_LEN + ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN
				         + masterFilenameBytes.length + file_size;
				
				hexLenBytes = ProtoCommon.long2buff(master_filename.length());
				System.arraycopy(hexLenBytes, 0, sizeBytes, 0, hexLenBytes.length);
				offset = hexLenBytes.length;
			}
			else
			{
				masterFilenameBytes = null;
				sizeBytes = new byte[1 + 1 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE];
        body_len = sizeBytes.length + ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN + file_size;

				sizeBytes[0] = (byte)this.storageServer.getStorePathIndex();
				offset = 1;
			}
			
			hexLenBytes = ProtoCommon.long2buff(file_size);
			System.arraycopy(hexLenBytes, 0, sizeBytes, offset, hexLenBytes.length);
			
			OutputStream out = storageSocket.getOutputStream();
			header = ProtoCommon.packHeader(cmd, body_len, (byte)0);
			byte[] wholePkg = new byte[(int)(header.length + body_len - file_size)];
			System.arraycopy(header, 0, wholePkg, 0, header.length);
			System.arraycopy(sizeBytes, 0, wholePkg, header.length, sizeBytes.length);
			offset = header.length + sizeBytes.length;
			if (bUploadSlave)
			{
				byte[] prefix_name_bs = new byte[ProtoCommon.FDFS_FILE_PREFIX_MAX_LEN];
				byte[] bs = prefix_name.getBytes(ClientGlobal.g_charset);
				int prefix_name_len = bs.length;
				Arrays.fill(prefix_name_bs, (byte)0);
				if (prefix_name_len > ProtoCommon.FDFS_FILE_PREFIX_MAX_LEN)
				{
					prefix_name_len = ProtoCommon.FDFS_FILE_PREFIX_MAX_LEN;
				}
				if (prefix_name_len > 0)
				{
					System.arraycopy(bs, 0, prefix_name_bs, 0, prefix_name_len);
				}
				
				System.arraycopy(prefix_name_bs, 0, wholePkg, offset, prefix_name_bs.length);
				offset += prefix_name_bs.length;
			}
			
			System.arraycopy(ext_name_bs, 0, wholePkg, offset, ext_name_bs.length);
			offset += ext_name_bs.length;
			
			if (bUploadSlave)
			{
				System.arraycopy(masterFilenameBytes, 0, wholePkg, offset, masterFilenameBytes.length);
				offset += masterFilenameBytes.length;
			}
			
			out.write(wholePkg);
			
			if ((this.errno=(byte)callback.send(out)) != 0)
			{
				return null;
			}
			
			ProtoCommon.RecvPackageInfo pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, -1);
			this.errno = pkgInfo.errno;
			if (pkgInfo.errno != 0)
			{
				return null;
			}
			
			if (pkgInfo.body.length <= ProtoCommon.FDFS_GROUP_NAME_MAX_LEN)
			{
				throw new MyException("body length: " + pkgInfo.body.length + " <= " + ProtoCommon.FDFS_GROUP_NAME_MAX_LEN);
			}
	
			new_group_name = new String(pkgInfo.body, 0, ProtoCommon.FDFS_GROUP_NAME_MAX_LEN).trim();
			remote_filename = new String(pkgInfo.body, ProtoCommon.FDFS_GROUP_NAME_MAX_LEN, pkgInfo.body.length - ProtoCommon.FDFS_GROUP_NAME_MAX_LEN);
			String[] results = new String[2];
			results[0] = new_group_name;
			results[1] = remote_filename;
			
			if (meta_list == null || meta_list.length == 0)
			{
				return results;
			}
			
			int result = 0;
			try
			{
				result = this.set_metadata(new_group_name, remote_filename, 
								meta_list, ProtoCommon.STORAGE_SET_METADATA_FLAG_OVERWRITE);
			}
			catch(IOException ex)
			{
				result = 5;
				throw ex;
			}
			finally
			{
				if (result != 0)
				{
					this.errno = (byte)result;
					this.delete_file(new_group_name, remote_filename);
					return null;
				}
			}
			
			return results;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}

	/**
	* append file to storage server
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_size the file size
	* @param callback the write data callback object
	* @return return true for success, false for fail
	*/
	protected int do_append_file(String group_name, String appender_filename, 
	         long file_size, UploadCallback callback) throws IOException, MyException
	{
		byte[] header;
		boolean bNewConnection;
		Socket storageSocket;
		byte[] hexLenBytes;
		byte[] appenderFilenameBytes;
		int offset;
		long body_len;

		if ((group_name == null || group_name.length() == 0) || 
		    (appender_filename == null || appender_filename.length() == 0))
		{
			this.errno = ProtoCommon.ERR_NO_EINVAL;
			return this.errno;
		}
		
		bNewConnection = this.newUpdatableStorageConnection(group_name, appender_filename);
		
		try
		{
			storageSocket = this.storageServer.getSocket();
						
			appenderFilenameBytes = appender_filename.getBytes(ClientGlobal.g_charset);
			body_len = 2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE + appenderFilenameBytes.length + file_size;
			
			header = ProtoCommon.packHeader(ProtoCommon.STORAGE_PROTO_CMD_APPEND_FILE, body_len, (byte)0);
			byte[] wholePkg = new byte[(int)(header.length + body_len - file_size)];
			System.arraycopy(header, 0, wholePkg, 0, header.length);
			offset = header.length;
			
			hexLenBytes = ProtoCommon.long2buff(appender_filename.length());
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;
			
			hexLenBytes = ProtoCommon.long2buff(file_size);
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;
			
			OutputStream out = storageSocket.getOutputStream();
			
			System.arraycopy(appenderFilenameBytes, 0, wholePkg, offset, appenderFilenameBytes.length);
			offset += appenderFilenameBytes.length;
			
			out.write(wholePkg);
			if ((this.errno=(byte)callback.send(out)) != 0)
			{
				return this.errno;
			}
			
			ProtoCommon.RecvPackageInfo pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, 0);
			this.errno = pkgInfo.errno;
			if (pkgInfo.errno != 0)
			{
				return this.errno;
			}
			
			return 0;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}

	/**
	* modify appender file to storage server
	* @param group_name the group name of appender file
	* @param appender_filename the appender filename
	* @param file_offset the offset of appender file
	* @param modify_size the modify size
	* @param callback the write data callback object
	* @return return true for success, false for fail
	*/
	protected int do_modify_file(String group_name, String appender_filename, 
	         long file_offset, long modify_size, UploadCallback callback) throws IOException, MyException
	{
		byte[] header;
		boolean bNewConnection;
		Socket storageSocket;
		byte[] hexLenBytes;
		byte[] appenderFilenameBytes;
		int offset;
		long body_len;

		if ((group_name == null || group_name.length() == 0) || 
		    (appender_filename == null || appender_filename.length() == 0))
		{
			this.errno = ProtoCommon.ERR_NO_EINVAL;
			return this.errno;
		}
		
		bNewConnection = this.newUpdatableStorageConnection(group_name, appender_filename);
		
		try
		{
			storageSocket = this.storageServer.getSocket();
						
			appenderFilenameBytes = appender_filename.getBytes(ClientGlobal.g_charset);
			body_len = 3 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE + appenderFilenameBytes.length + modify_size;
			
			header = ProtoCommon.packHeader(ProtoCommon.STORAGE_PROTO_CMD_MODIFY_FILE, body_len, (byte)0);
			byte[] wholePkg = new byte[(int)(header.length + body_len - modify_size)];
			System.arraycopy(header, 0, wholePkg, 0, header.length);
			offset = header.length;
			
			hexLenBytes = ProtoCommon.long2buff(appender_filename.length());
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;

			hexLenBytes = ProtoCommon.long2buff(file_offset);
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;
			
			hexLenBytes = ProtoCommon.long2buff(modify_size);
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;
			
			OutputStream out = storageSocket.getOutputStream();
			
			System.arraycopy(appenderFilenameBytes, 0, wholePkg, offset, appenderFilenameBytes.length);
			offset += appenderFilenameBytes.length;
			
			out.write(wholePkg);
			if ((this.errno=(byte)callback.send(out)) != 0)
			{
				return this.errno;
			}
			
			ProtoCommon.RecvPackageInfo pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, 0);
			this.errno = pkgInfo.errno;
			if (pkgInfo.errno != 0)
			{
				return this.errno;
			}
						
			return 0;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* delete file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @return 0 for success, none zero for fail (error code)
	*/
	public int delete_file(String group_name, String remote_filename) throws IOException, MyException
	{
		boolean bNewConnection = this.newUpdatableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		
		try
		{
			this.send_package(ProtoCommon.STORAGE_PROTO_CMD_DELETE_FILE, group_name, remote_filename);
			ProtoCommon.RecvPackageInfo pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, 0);
			
			this.errno = pkgInfo.errno;
			return pkgInfo.errno;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* truncate appender file to size 0 from storage server
	* @param group_name the group name of storage server
	*	@param appender_filename the appender filename
	* @return 0 for success, none zero for fail (error code)
	*/
	public int truncate_file(String group_name, String appender_filename) throws IOException, MyException
	{
		final long truncated_file_size = 0;
		return this.truncate_file(group_name, appender_filename, truncated_file_size);
	}
	
	/**
	* truncate appender file from storage server
	* @param group_name the group name of storage server
	*	@param appender_filename the appender filename
	* @param truncated_file_size truncated file size
	* @return 0 for success, none zero for fail (error code)
	*/
	public int truncate_file(String group_name, String appender_filename, 
			long truncated_file_size) throws IOException, MyException
	{
		byte[] header;
		boolean bNewConnection;
		Socket storageSocket;
		byte[] hexLenBytes;
		byte[] appenderFilenameBytes;
		int offset;
		int body_len;

		if ((group_name == null || group_name.length() == 0) || 
		    (appender_filename == null || appender_filename.length() == 0))
		{
			this.errno = ProtoCommon.ERR_NO_EINVAL;
			return this.errno;
		}
		
		bNewConnection = this.newUpdatableStorageConnection(group_name, appender_filename);
		
		try
		{
			storageSocket = this.storageServer.getSocket();
						
			appenderFilenameBytes = appender_filename.getBytes(ClientGlobal.g_charset);
			body_len = 2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE + appenderFilenameBytes.length;
			
			header = ProtoCommon.packHeader(ProtoCommon.STORAGE_PROTO_CMD_TRUNCATE_FILE, body_len, (byte)0);
			byte[] wholePkg = new byte[header.length + body_len];
			System.arraycopy(header, 0, wholePkg, 0, header.length);
			offset = header.length;
			
			hexLenBytes = ProtoCommon.long2buff(appender_filename.length());
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;
			
			hexLenBytes = ProtoCommon.long2buff(truncated_file_size);
			System.arraycopy(hexLenBytes, 0, wholePkg, offset, hexLenBytes.length);
			offset += hexLenBytes.length;
			
			OutputStream out = storageSocket.getOutputStream();
			
			System.arraycopy(appenderFilenameBytes, 0, wholePkg, offset, appenderFilenameBytes.length);
			offset += appenderFilenameBytes.length;
			
			out.write(wholePkg);
			ProtoCommon.RecvPackageInfo pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, 0);
			this.errno = pkgInfo.errno;
			return pkgInfo.errno;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* download file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @return file content/buff, return null if fail
	*/
	public byte[] download_file(String group_name, String remote_filename) throws IOException, MyException
	{
		final long file_offset = 0;
		final long download_bytes = 0;
		
		return this.download_file(group_name, remote_filename, file_offset, download_bytes);
	}
	
	/**
	* download file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @param file_offset the start offset of the file
	* @param download_bytes download bytes, 0 for remain bytes from offset
	* @return file content/buff, return null if fail
	*/
	public byte[] download_file(String group_name, String remote_filename, long file_offset, long download_bytes) throws IOException, MyException
	{
		boolean bNewConnection = this.newReadableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		
		try
		{
			ProtoCommon.RecvPackageInfo pkgInfo;
			
			this.send_download_package(group_name, remote_filename, file_offset, download_bytes);
			pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, -1);
			
			this.errno = pkgInfo.errno;
			if (pkgInfo.errno != 0)
			{
				return null;
			}
			
			return pkgInfo.body;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}

	/**
	* download file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @param local_filename  filename on local
	* @return 0 success, return none zero errno if fail
	*/
	public int download_file(String group_name, String remote_filename, 
	                  String local_filename) throws IOException, MyException
	{
		final long file_offset = 0;
		final long download_bytes = 0;
		return this.download_file(group_name, remote_filename, 
	                  file_offset, download_bytes, local_filename);
	}
	
	/**
	* download file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
  * @param file_offset the start offset of the file
	* @param download_bytes download bytes, 0 for remain bytes from offset
	* @param local_filename  filename on local
	* @return 0 success, return none zero errno if fail
	*/
	public int download_file(String group_name, String remote_filename, 
	                  long file_offset, long download_bytes, 
	                  String local_filename) throws IOException, MyException
	{
		boolean bNewConnection = this.newReadableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		try
		{
			ProtoCommon.RecvHeaderInfo header;
			FileOutputStream out = new FileOutputStream(local_filename);
			try
			{
				this.errno = 0;
				this.send_download_package(group_name, remote_filename, file_offset, download_bytes);
				
				InputStream in = storageSocket.getInputStream();
				header = ProtoCommon.recvHeader(in, ProtoCommon.STORAGE_PROTO_CMD_RESP, -1);
				this.errno = header.errno;
				if (header.errno != 0)
				{
					return header.errno;
				}
				
				byte[] buff = new byte[256 * 1024];
				long remainBytes = header.body_len;
				int bytes;
				
				//System.out.println("expect_body_len=" + header.body_len);
				
				while (remainBytes > 0)
				{
					if ((bytes=in.read(buff, 0, remainBytes > buff.length ? buff.length : (int)remainBytes)) < 0)
					{
						throw new IOException("recv package size " + (header.body_len - remainBytes) + " != " + header.body_len);
					}
					
					out.write(buff, 0, bytes);
					remainBytes -= bytes;
					
					//System.out.println("totalBytes=" + (header.body_len - remainBytes));
				}
				
				return 0;
			}
			catch(IOException ex)
			{
				if (this.errno == 0)
				{
					this.errno = ProtoCommon.ERR_NO_EIO;
				}
				
				throw ex;
			}
			finally
			{
				out.close();
				if (this.errno != 0)
				{
					(new File(local_filename)).delete();
				}
			}
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* download file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @param callback call callback.recv() when data arrive
	* @return 0 success, return none zero errno if fail
	*/
	public int download_file(String group_name, String remote_filename, 
	                  DownloadCallback callback) throws IOException, MyException
	{
		final long file_offset = 0;
		final long download_bytes = 0;
		return this.download_file(group_name, remote_filename, 
	                  file_offset, download_bytes, callback);
	}
	
	/**
	* download file from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
  * @param file_offset the start offset of the file
	* @param download_bytes download bytes, 0 for remain bytes from offset
	* @param callback call callback.recv() when data arrive
	* @return 0 success, return none zero errno if fail
	*/
	public int download_file(String group_name, String remote_filename, 
	                  long file_offset, long download_bytes, 
	                  DownloadCallback callback) throws IOException, MyException
	{
		int result;
		boolean bNewConnection = this.newReadableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		
		try
		{
			  ProtoCommon.RecvHeaderInfo header;
				this.send_download_package(group_name, remote_filename, file_offset, download_bytes);
				
				InputStream in = storageSocket.getInputStream();
				header = ProtoCommon.recvHeader(in, ProtoCommon.STORAGE_PROTO_CMD_RESP, -1);
				this.errno = header.errno;
				if (header.errno != 0)
				{
					return header.errno;
				}
				
				byte[] buff = new byte[2 * 1024];
				long remainBytes = header.body_len;
				int bytes;
				
				//System.out.println("expect_body_len=" + header.body_len);
				
				while (remainBytes > 0)
				{
					if ((bytes=in.read(buff, 0, remainBytes > buff.length ? buff.length : (int)remainBytes)) < 0)
					{
						throw new IOException("recv package size " + (header.body_len - remainBytes) + " != " + header.body_len);
					}
					
					if ((result=callback.recv(header.body_len, buff, bytes)) != 0)
					{
						this.errno = (byte)result;
						return result;
					}
					
					remainBytes -= bytes;
					//System.out.println("totalBytes=" + (header.body_len - remainBytes));
				}
				
				return 0;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* get all metadata items from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @return meta info array, return null if fail
	*/
	public NameValuePair[] get_metadata(String group_name, String remote_filename)throws IOException, MyException
	{
		boolean bNewConnection = this.newUpdatableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		
		try
		{
			ProtoCommon.RecvPackageInfo pkgInfo;
			
			this.send_package(ProtoCommon.STORAGE_PROTO_CMD_GET_METADATA, group_name, remote_filename);
			pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, -1);
			
			this.errno = pkgInfo.errno;
			if (pkgInfo.errno != 0)
			{
				return null;
			}
			
			return ProtoCommon.split_metadata(new String(pkgInfo.body, ClientGlobal.g_charset));
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* set metadata items to storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	*	@param meta_list meta item array
	* @param op_flag flag, can be one of following values: <br>
	*            <ul><li> ProtoCommon.STORAGE_SET_METADATA_FLAG_OVERWRITE: overwrite all old
	*				       metadata items</li></ul>
	*            <ul><li> ProtoCommon.STORAGE_SET_METADATA_FLAG_MERGE: merge, insert when
	*				       the metadata item not exist, otherwise update it</li></ul>
	* @return 0 for success, !=0 fail (error code)
	*/
	public int set_metadata(String group_name, String remote_filename, 
							NameValuePair[] meta_list, byte op_flag) throws IOException, MyException
	{
		boolean bNewConnection = this.newUpdatableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		
		try
		{
			byte[] header;
			byte[] groupBytes;
			byte[] filenameBytes;
			byte[] meta_buff;
			byte[] bs;
			int groupLen;
			byte[] sizeBytes;
			ProtoCommon.RecvPackageInfo pkgInfo;
			
			if (meta_list == null)
			{
				meta_buff = new byte[0];
			}
			else
			{
				meta_buff = ProtoCommon.pack_metadata(meta_list).getBytes(ClientGlobal.g_charset);
			}
			
			filenameBytes = remote_filename.getBytes(ClientGlobal.g_charset);
			sizeBytes = new byte[2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE];
			Arrays.fill(sizeBytes, (byte)0);
			
			bs = ProtoCommon.long2buff(filenameBytes.length);
			System.arraycopy(bs, 0, sizeBytes, 0, bs.length);
			bs = ProtoCommon.long2buff(meta_buff.length);
			System.arraycopy(bs, 0, sizeBytes, ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE, bs.length);
			
			groupBytes = new byte[ProtoCommon.FDFS_GROUP_NAME_MAX_LEN];
			bs = group_name.getBytes(ClientGlobal.g_charset);
			
			Arrays.fill(groupBytes, (byte)0);
			if (bs.length <= groupBytes.length)
			{
				groupLen = bs.length;
			}
			else
			{
				groupLen = groupBytes.length;
			}
			System.arraycopy(bs, 0, groupBytes, 0, groupLen);
			
			header = ProtoCommon.packHeader(ProtoCommon.STORAGE_PROTO_CMD_SET_METADATA, 
			           2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE + 1 + groupBytes.length
			           + filenameBytes.length + meta_buff.length, (byte)0);
			OutputStream out = storageSocket.getOutputStream();
			byte[] wholePkg = new byte[header.length + sizeBytes.length + 1 + groupBytes.length + filenameBytes.length];
			System.arraycopy(header, 0, wholePkg, 0, header.length);
			System.arraycopy(sizeBytes, 0, wholePkg, header.length, sizeBytes.length);
			wholePkg[header.length+sizeBytes.length] = op_flag;
			System.arraycopy(groupBytes, 0, wholePkg, header.length+sizeBytes.length+1, groupBytes.length);
			System.arraycopy(filenameBytes, 0, wholePkg, header.length+sizeBytes.length+1+groupBytes.length, filenameBytes.length);
			out.write(wholePkg);
			if (meta_buff.length > 0)
			{
		  	out.write(meta_buff);
		  }
		  
			pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, 0);
			
			this.errno = pkgInfo.errno;
			return pkgInfo.errno;
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}

	/**
	* get file info decoded from the filename, fetch from the storage if necessary
	* @param group_name the group name
	*	@param remote_filename the filename
	* @return FileInfo object for success, return null for fail
	*/
	public FileInfo get_file_info(String group_name, String remote_filename) throws IOException, MyException
	{
	  if (remote_filename.length() < ProtoCommon.FDFS_FILE_PATH_LEN + ProtoCommon.FDFS_FILENAME_BASE64_LENGTH
	                   + ProtoCommon.FDFS_FILE_EXT_NAME_MAX_LEN + 1)
	  {
	          this.errno = ProtoCommon.ERR_NO_EINVAL;
	          return null;
	  }
	  
	  byte[] buff = base64.decodeAuto(remote_filename.substring(ProtoCommon.FDFS_FILE_PATH_LEN, 
	  	ProtoCommon.FDFS_FILE_PATH_LEN + ProtoCommon.FDFS_FILENAME_BASE64_LENGTH));
		
	  long file_size = ProtoCommon.buff2long(buff, 4 * 2);
	  if (((remote_filename.length() > ProtoCommon.TRUNK_LOGIC_FILENAME_LENGTH) || 
	          ((remote_filename.length() > ProtoCommon.NORMAL_LOGIC_FILENAME_LENGTH) && ((file_size & ProtoCommon.TRUNK_FILE_MARK_SIZE) == 0))) || 
	          ((file_size & ProtoCommon.APPENDER_FILE_SIZE) != 0))
	  { //slave file or appender file
	  	FileInfo fi = this.query_file_info(group_name, remote_filename);
	  	if (fi == null)
	  	{
	  		return null;
	  	}
	  	return fi;
	  }
	  
		FileInfo fileInfo = new FileInfo(file_size, 0, 0, ProtoCommon.getIpAddress(buff, 0));
    fileInfo.setCreateTimestamp(ProtoCommon.buff2int(buff, 4));
    if ((file_size >> 63) != 0)
    {
	    file_size &= 0xFFFFFFFFL;  //low 32 bits is file size
	    fileInfo.setFileSize(file_size);
    }
    fileInfo.setCrc32(ProtoCommon.buff2int(buff, 4 * 4));
	  
	  return fileInfo;
	}

	/**
	* get file info from storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @return FileInfo object for success, return null for fail
	*/
	public FileInfo query_file_info(String group_name, String remote_filename) throws IOException, MyException
	{
		boolean bNewConnection = this.newUpdatableStorageConnection(group_name, remote_filename);
		Socket storageSocket = this.storageServer.getSocket();
		
		try
		{
			byte[] header;
			byte[] groupBytes;
			byte[] filenameBytes;
			byte[] bs;
			int groupLen;
			ProtoCommon.RecvPackageInfo pkgInfo;
			
			filenameBytes = remote_filename.getBytes(ClientGlobal.g_charset);			
			groupBytes = new byte[ProtoCommon.FDFS_GROUP_NAME_MAX_LEN];
			bs = group_name.getBytes(ClientGlobal.g_charset);
			
			Arrays.fill(groupBytes, (byte)0);
			if (bs.length <= groupBytes.length)
			{
				groupLen = bs.length;
			}
			else
			{
				groupLen = groupBytes.length;
			}
			System.arraycopy(bs, 0, groupBytes, 0, groupLen);
			
			header = ProtoCommon.packHeader(ProtoCommon.STORAGE_PROTO_CMD_QUERY_FILE_INFO, 
			           + groupBytes.length + filenameBytes.length, (byte)0);
			OutputStream out = storageSocket.getOutputStream();
			byte[] wholePkg = new byte[header.length + groupBytes.length + filenameBytes.length];
			System.arraycopy(header, 0, wholePkg, 0, header.length);
			System.arraycopy(groupBytes, 0, wholePkg, header.length, groupBytes.length);
			System.arraycopy(filenameBytes, 0, wholePkg, header.length + groupBytes.length, filenameBytes.length);
			out.write(wholePkg);
		  
			pkgInfo = ProtoCommon.recvPackage(storageSocket.getInputStream(), 
	                                     ProtoCommon.STORAGE_PROTO_CMD_RESP, 
	                                     3 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE + 
	                                     ProtoCommon.FDFS_IPADDR_SIZE);
			
			this.errno = pkgInfo.errno;
			if (pkgInfo.errno != 0)
			{
				return null;
			}
			
			long file_size = ProtoCommon.buff2long(pkgInfo.body, 0);
			int create_timestamp = (int)ProtoCommon.buff2long(pkgInfo.body, ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE);
			int crc32 = (int)ProtoCommon.buff2long(pkgInfo.body, 2 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE);
			String source_ip_addr = (new String(pkgInfo.body, 3 * ProtoCommon.FDFS_PROTO_PKG_LEN_SIZE, ProtoCommon.FDFS_IPADDR_SIZE)).trim();
			return new FileInfo(file_size, create_timestamp, crc32, source_ip_addr);
		}
		catch(IOException ex)
		{
			if (!bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
			
			throw ex;
		}
		finally
		{
			if (bNewConnection)
			{
				try
				{
					this.storageServer.close();
				}
				catch(IOException ex1)
				{
					ex1.printStackTrace();
				}
				finally
				{
					this.storageServer = null;
				}
			}
		}
	}
	
	/**
	* check storage socket, if null create a new connection
	* @param group_name the group name to upload file to, can be empty
	* @return true if create a new connection
	*/
	protected boolean newWritableStorageConnection(String group_name) throws IOException, MyException
	{
		if (this.storageServer != null)
		{
			return false;
		}
		else
		{
			TrackerClient tracker = new TrackerClient();
  		this.storageServer = tracker.getStoreStorage(this.trackerServer, group_name);
  		if (this.storageServer == null)
  		{
  			throw new MyException("getStoreStorage fail, errno code: " + tracker.getErrorCode());
  		}
  		return true;
		}
  }

	/**
	* check storage socket, if null create a new connection
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @return true if create a new connection
	*/
	protected boolean newReadableStorageConnection(String group_name, String remote_filename) throws IOException, MyException
	{
		if (this.storageServer != null)
		{
			return false;
		}
		else
		{
			TrackerClient tracker = new TrackerClient();
  		this.storageServer = tracker.getFetchStorage(this.trackerServer, group_name, remote_filename);
  		if (this.storageServer == null)
  		{
  			throw new MyException("getStoreStorage fail, errno code: " + tracker.getErrorCode());
  		}
  		return true;
		}
  }

	/**
	* check storage socket, if null create a new connection
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @return true if create a new connection
	*/
	protected boolean newUpdatableStorageConnection(String group_name, String remote_filename) throws IOException, MyException
	{
		if (this.storageServer != null)
		{
			return false;
		}
		else
		{
			TrackerClient tracker = new TrackerClient();
  		this.storageServer = tracker.getUpdateStorage(this.trackerServer, group_name, remote_filename);
  		if (this.storageServer == null)
  		{
  			throw new MyException("getStoreStorage fail, errno code: " + tracker.getErrorCode());
  		}
  		return true;
		}
  }
  
	/**
	* send package to storage server
	* @param cmd which command to send
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	*/
	protected void send_package(byte cmd, String group_name, String remote_filename) throws IOException
	{
		byte[] header;
		byte[] groupBytes;
		byte[] filenameBytes;
		byte[] bs;
		int groupLen;
				
		groupBytes = new byte[ProtoCommon.FDFS_GROUP_NAME_MAX_LEN];
		bs = group_name.getBytes(ClientGlobal.g_charset);
		filenameBytes = remote_filename.getBytes(ClientGlobal.g_charset);
		
		Arrays.fill(groupBytes, (byte)0);
		if (bs.length <= groupBytes.length)
		{
			groupLen = bs.length;
		}
		else
		{
			groupLen = groupBytes.length;
		}
		System.arraycopy(bs, 0, groupBytes, 0, groupLen);
		
		header = ProtoCommon.packHeader(cmd, groupBytes.length + filenameBytes.length, (byte)0);
		byte[] wholePkg = new byte[header.length + groupBytes.length + filenameBytes.length];
		System.arraycopy(header, 0, wholePkg, 0, header.length);
		System.arraycopy(groupBytes, 0, wholePkg, header.length, groupBytes.length);
		System.arraycopy(filenameBytes, 0, wholePkg, header.length+groupBytes.length, filenameBytes.length);
		this.storageServer.getSocket().getOutputStream().write(wholePkg);
	}
	
	/**
	* send package to storage server
	* @param group_name the group name of storage server
	*	@param remote_filename filename on storage server
	* @param file_offset the start offset of the file
	* @param download_bytes download bytes
	*/
	protected void send_download_package(String group_name, String remote_filename, long file_offset, long download_bytes) throws IOException
	{
		byte[] header;
		byte[] bsOffset;
		byte[] bsDownBytes;
		byte[] groupBytes;
		byte[] filenameBytes;
		byte[] bs;
		int groupLen;
		
		bsOffset = ProtoCommon.long2buff(file_offset);
		bsDownBytes = ProtoCommon.long2buff(download_bytes);
		groupBytes = new byte[ProtoCommon.FDFS_GROUP_NAME_MAX_LEN];
		bs = group_name.getBytes(ClientGlobal.g_charset);
		filenameBytes = remote_filename.getBytes(ClientGlobal.g_charset);
		
		Arrays.fill(groupBytes, (byte)0);
		if (bs.length <= groupBytes.length)
		{
			groupLen = bs.length;
		}
		else
		{
			groupLen = groupBytes.length;
		}
		System.arraycopy(bs, 0, groupBytes, 0, groupLen);
		
		header = ProtoCommon.packHeader(ProtoCommon.STORAGE_PROTO_CMD_DOWNLOAD_FILE, 
             bsOffset.length + bsDownBytes.length + groupBytes.length + filenameBytes.length, (byte)0);
		byte[] wholePkg = new byte[header.length + bsOffset.length + bsDownBytes.length + groupBytes.length + filenameBytes.length];
		System.arraycopy(header, 0, wholePkg, 0, header.length);
		System.arraycopy(bsOffset, 0, wholePkg, header.length, bsOffset.length);
		System.arraycopy(bsDownBytes, 0, wholePkg, header.length+bsOffset.length, bsDownBytes.length);
		System.arraycopy(groupBytes, 0, wholePkg, header.length+bsOffset.length+bsDownBytes.length, groupBytes.length);
		System.arraycopy(filenameBytes, 0, wholePkg, header.length+bsOffset.length+bsDownBytes.length+groupBytes.length, filenameBytes.length);
		this.storageServer.getSocket().getOutputStream().write(wholePkg);
	}
}
